fission

noun
fis·​sion | \ ˈfi-shᵊn How to pronounce fission (audio) , -zhᵊn \

Definition of fission

 (Entry 1 of 2)

1 : a splitting or breaking up into parts
2 : reproduction by spontaneous division of the body into two or more parts each of which grows into a complete organism
3 : the splitting of an atomic nucleus resulting in the release of large amounts of energy

fission

verb
fissioned; fissioning; fissions

Definition of fission (Entry 2 of 2)

intransitive verb

: to undergo fission

transitive verb

: to cause to undergo fission

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Other Words from fission

Noun

fissional \ ˈfi-​shə-​nəl How to pronounce fission (audio) , -​zhə-​ \ adjective

Examples of fission in a Sentence

Recent Examples on the Web: Noun Like their bigger brothers, SMRs use nuclear fission to generate carbon-free electricity, though on a much smaller scale – typically in the 50 megawatt to 400 megawatt range compared. Ariel Cohen, Forbes, 27 Sep. 2021 While fission splits the nuclei of atoms to create power, fusion causes hydrogen nuclei to collide and fuse into helium atoms that release tremendous amounts of energy. Rob Nikolewski, San Diego Union-Tribune, 26 Sep. 2021 In 1939, Albert Einstein wrote to President Roosevelt warning of fission chain reactions utilizing uranium that could likely produce large amounts of power, and his belief that Germany was pursuing the research. Doug Strickland, Popular Mechanics, 6 Sep. 2021 Like traditional nuclear fission power, which splits atoms, fusion energy would not consume fossil fuel and would not produce greenhouse gases. New York Times, 10 Aug. 2021 Ultimately, the Manhattan Project succeeded in building two atomic bomb designs: one that relied on the nuclear fission of uranium and the other based on plutonium, per History.com. Nora Mcgreevy, Smithsonian Magazine, 30 Aug. 2021 Nuclear fusion is different from the nuclear fission process seen at commercial nuclear power plants, such as the now-shuttered San Onofre Nuclear Generating Station. Rob Nikolewski, San Diego Union-Tribune, 10 Aug. 2021 The fundamental breakthroughs needed to make abundant zero-carbon electricity a reality—better energy storage, next-generation nuclear fission, viable nuclear fusion—are first and foremost physical engineering challenges. Rob Toews, Forbes, 20 June 2021 Experts said that suggested fuel rods broke and leaked radioactive gas produced during nuclear fission. Joe Mcdonald, ajc, 16 June 2021 Recent Examples on the Web: Verb The point is that by analyzing the array of radioactive fission products – those that can be captured and analyzed – nuclear forensic specialists can start to figure out if the atoms that fissioned were U-235, Pu-239, or (in some cases) U-238. Andrew Karam, Popular Mechanics, 7 Jan. 2016 Anyone can see that fissioning uranium 235 or plutonium can be used to generate electricity. Scientific American, 1 Jan. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fission.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of fission

Noun

circa 1617, in the meaning defined at sense 1

Verb

1929, in the meaning defined at intransitive sense

History and Etymology for fission

Noun

borrowed from Latin fissiōn-, fissiō, from fid-, variant stem of findere "to split, cleave" + -tiōn-, -tiō, suffix of verbal action — more at bite entry 1

Verb

derivative of fission entry 1

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Time Traveler for fission

Time Traveler

The first known use of fission was circa 1617

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Dictionary Entries Near fission

Fissilinguia

fission

fissionable

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Statistics for fission

Last Updated

1 Oct 2021

Cite this Entry

“Fission.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fission. Accessed 25 Oct. 2021.

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More Definitions for fission

fission

noun

English Language Learners Definition of fission

: a process in which the nucleus of a heavy atom is split apart
: a kind of reproduction in which a cell or body divides into two or more parts and each part grows into a whole new individual

fission

noun
fis·​sion | \ ˈfi-shən How to pronounce fission (audio) \

Kids Definition of fission

1 : a method of reproduction in which a living cell or body divides into two or more parts each of which grows into a whole new individual
2 : the process of splitting an atomic nucleus with the release of large amounts of energy

fission

noun
fis·​sion | \ ˈfish-ən also ˈfizh- How to pronounce fission (audio) \

Medical Definition of fission

1 : a method of reproduction in which a living cell or body divides into two or more parts each of which grows into a whole new individual
b : the splitting of an atomic nucleus resulting in the release of large amounts of energy

called also nuclear fission

Other Words from fission

fission verb fissioned; fissioning\ ˈfish-​(ə-​)niŋ also ˈfizh-​ How to pronounce fission (audio) \
fissional \ ˈfish-​ən-​ᵊl also ˈfizh-​ How to pronounce fission (audio) \ adjective

More from Merriam-Webster on fission

Nglish: Translation of fission for Spanish Speakers

Britannica English: Translation of fission for Arabic Speakers

Britannica.com: Encyclopedia article about fission

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